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Status : Active
Standard Type : Main
Document No : ISO 23697-1:2023
Document Year : 2023
Pages : 9
Edition : 1
Section Volume : Physical, chemical and biochemical methods (ISO/TC 147/SC 2.)
The measuring ranges can vary depending on the type of small-scale sealed tube method of different manufacturers. It is up to the user to choose the small-scale sealed tube with the appropriate application range or to adapt samples with concentrations exceeding the measuring range of a test by preliminary dilution.
NOTE The results of a small-scale sealed tube are most precise in the middle of the application range of the test.
All small-scale sealed tube methods are based on a heated alkaline potassium persulfate oxidation in a heating block. Different digestion temperatures, 100 °C or 120 °C or 170 °C, and different digestion times are applicable. Dimethylphenol colour reactions are applied, depending on the typical operating procedure of the small-scale sealed tube used, see Clause 9.